Film retention means for film cartridges

ABSTRACT

A film cartridge for a projector having an end of film sensing means for blocking the film driving means from feeding film into the cartridge while maintaining engagement of the film end with the driving means whereby the driving means can conveniently feed the film out of the cartridge.

United States Patent [19] Schmidt [54] 'FILM RETENTION MEANS FOR FILMCARTRIDGES Josef Schmidt, Chicago, Ill.

Bell & Howell Company, Chicago, Ill.

Filed: Sept. 23, 1971 Appl. No.:- 183,125

Inventor:

Assignee:

U.S. Cl. ..226/l1, 352/78, 226/127, 242/57 Int. Cl. ..B65h 25/00 Fieldof Search ..226/1 1, 127; 242/57; 352/78 [56] References Cited UNITED sATEs PATENTS 3,559,918 2/1971 Braun ..352/78 R 3,737,086 June 5, 19739,458,157" 7/1969 Wells .;.....'..242 s7x 7/1956 Dornellas ..242/57XPrimary ExaminerAllen N. Knowles 1 Attorney- Kenneth W. Greb, John E'.Peele, Jr., William K. Serp and Nicholas A. Camasto 57 ABSTRACT I A filmcartridge for a projector having an end of film sensing means forblocking the film driving means from feeding film into the cartridgewhile maintaining engagement of the film end with the driving meanswhereby the driving means can conveniently feed the film out of thecartridge.

2 Claims, 4 Drawing Figures 9 FILM RETENTION MEANS FOR FILM CARTRIDGESThis invention relates to an end of film retention means for filmcartridges for use in a projector, and is particularly concerned. withmeans for maintaining the BACKGROUND OF THE INVENTION In the projectionof a filmstrip, it is customary to rewind the filmstrip in the magazineafter it has been projected. In cartridges, the filmstrip is driven bysprocket wheels that are rotated manually or by any suitable reversiblemotor with radially projecting teeth engaging the film apertures.Heretofore it has been practically impossible to rewind the filmstrip inthe magazine and stop the drive means before total disengagement of thefilm apertures and the driving teeth. Therefore it has been necessary tore-engage the apertures adjacent the trailing end of the filmstrip withthe driving teeth in order to pull the filmstrip out of the magazinewhen the teeth are rotated in the opposite direction.

SUMMARY OF THE INVENTION In the cartridge constructed in accordance withthe present invention, the movement of the filmstrip into the magazineis stopped automatically while the apertures adjacent the trailing endof the filmstrip are still engaged by the teeth of the sprocket wheels.When the rotation of the sprocket wheels is reversed, the teeth pull thefilm out of the magazine, thus eliminating the necessity of re-engagingthe film apertures with the teeth.

The cartridge is similar in many respects to the cartridge disclosed inthe co-pending applications, Ser. No. 97,859, filed Dec. 14, 1970, nowU.S. Pat. No. 3675994, and Ser. No. 163,155, I filed July 16, l97l,andassigned to the same assignee as this invention. The essentialdifference between the cartridges is that in the co-pending applicationthe film feed is stopped without stopping the rotation of the sprocketwheels, and in this application the film feed is stopped by stopping therotation of the sprocket wheels.

The object of the present invention is to provide an end of filmretention means for a projector including a cartridge for storing film,a driving means for feeding film into and out of the cartridge, and anend of film sensing means operable for blocking the film driving meansfrom feeding film into the cartridge while maintaining engagement of thefilm end with the driving means.

Suitable structure by means of which the above noted and otheradvantages are attained will be fully described in the followingspecification, taken in conjunction with the accompanying drawingsshowing a prefe'rred embodiment of the invention; in which:

FIG. 1 is a perspective view of a cartridge embodying the invention withone side broken away to illustrate the interior structure:

FIG. 2 is a side elevational view with one side wall of the cartridgeremoved showing the invention in a film feeding condition;

FIG. 3 is a view similar to the left end portion of FIG.

2 showing the invention in a film blocking condition;

and

FIG. 4 is a cross-sectional view taken along the line 4-4 of FIG. 2.

DESCRIPTION-OF THE ILLUSTRATED EMBODIMENT In the'drawings, the cartridgecomprises a base 10 and a housing 11 each preferably molded of suitableplastic material as a separate integral unit. The housing ect inwardlyfrom the inner surface of the front wall and upwardly from the basethroughout the length of the roller feed compartment and into themagazine. The guide rails are spaced apart a distance slightly less thanthe width of the filmstrip and are adapted to engage the longitudinaledge portion of the filmstrip outwardly of its apertures to support itas it is moved into or out of the magazine.

The housing 11 comprises a pair of side walls 17 and 18 that cooperatewith a back wall 19, a top wall 20, and a vertically disposedintermediate wall 21 depending from the front edge of the top wall 20 toform a magazine in which the filmstrip is stored in coiled form. Thewalls of the magazine cause the filmstrip to be wound in coil formationas it is fed into the magazine, but, if desired, the magazine may beprovided with a spring pressed arcuate plate that restrains the coiledfilmstrip in the magazine, as disclosed in the aboveidentifiedco-pending application.

The housing also includes a horizontally disposedend in spacedrelationship to the upper edge of the front wall 14.

The rear end of the housing 11 is pivotally secured to the base 10 byinterengageable pin and aperture connections. The base is provided witha pair of parallel cars 24 that project upwardly from the rear endportion of the base outwardly of the guide rails 16. Each ear has a.hinge pin 25 projecting inwardly therefrom in axial alignment. Each ofthe side walls 17. and 18 has an aperture 26 adapted to be aligned withthe hinge pins 25. The side walls 17 and 18 are sufficiently resilientto be snapped into place with the apertures 26 engaging the adjacenthinge pins 25. The front end of the housing 11 may be detachably securedto the base in any suitable manner. Preferably each of the guide rails16 has a boss 27 projecting outwardly therefrom. The side walls 17 and18 are each provided with an aperture 28 that are adapted to be snappedover the bosses 27 to hold the housing in its closed position. The outerends of the bosses 27 are rounded to permit the side walls to' bereadily disengaged from the bosses when the cartridge is to be opened.

The lower portion of the vertical wall 21, which separates the rollerfeed compartment from the magazine, is reinforced by laterally spacedvertical flanges 29 that project forwardly into the feed rollercompartment. The vertical wall 21 and the flanges 29 terminate a shortdistance above the upper edges of the guide rails 16 to provide ahorizontal passageway 30 through which the filmstrip passes as it is fedinto and out of the magazine. A spring 31 has one end secured to thelower portion of the wall 21 adjacent the side wall 17. The lower end ofthe spring 31 projects forwardly into the roller feed compartment for apurpose hereinafter disclosed.

The means for feeding the film in both directions comprises a pair ofsprocket wheels 32 and 33 integral with a tubular member 34 axiallyaligned therewith. Each of the sprocket wheels 32 and 33 is providedwith a plurality of radially extending sprocket teeth 35 spacedcircumferentially to coincide with the longitudinal spacing of theapertures 36 in a conventional filmstrip 37. The lateral spacing betweenthe teeth of sprocket wheels 32 and 33 is the same as the lateralspacing between the apertures 36. The forward end portions of the sidewalls 17 and 18 have suitable provisions for pivotably supporting thetubular member 34.

When the tubular member 34 is mounted in the fed roller compartment, thefront peripheral edge portions of the sprocket wheels are close to theupper edge portion of the front wall 14 and form a restricted zoneadjacent the upper edge of the front wall 14. The circumferencedescribed by the outer edges of the teeth 35 extends forwardly of theplane described by the outer edges of the guide rails 16 projectingrearwardly from 1 the inner surface of the front wall 14. A pair of ribs46 extend rearwardly from the front wall 14 in transversely spacedrelationship between the guide rails 16. The ribs 46 are parallel to theguide rails 16 and project inwardly to the same extent as the guiderails 16. As the filmstrip 37 enters the restricted zone between thesprocket wheels 32 and 33 and the front wall 14, the guide rails 16 andthe ribs 46 press the film toward the sprocket wheels 32 and 33 to movethe apertures 36 of the film 37 into driving engagement with thesprocket teeth 32 and 33. The stripper plate 23 insures separa tion ofthe film 37 from the sprocket teeth 32 and 33 as the film 37 movesupwardly out of the restricted zone. The apertures 36 of the film 37moving downwardly through the restricted zone remain in engagement withthe sprocket teeth 32 and 33 until the teeth pass through the verticalplane at the lowermost edge of the sprocket wheels 32 and 33.

The sprocket wheels 32 and 33 are driven by a shaft 47 rotatably mountedin the axial bore of the tubular member 34. The shaft 47 may be rotatedmanually or by any suitable reversible motor. The shaft 47 has anaxially extending finger 53 engageable with a toothed portion 51 in thetubular member 34 for rotating the sprocket wheels 32 and 33 in eitherdirection. Rotation of the sprocket wheels 32 and 33 in one direction,with plate 57 to move pivotally about the pin 58 which is 10- catedoutside the perimeter of the opening 59.

The outer side of the sprocket wheel 32, adjacent the plate 57, isrecessed at a plurality of circumferentially spaced intervals to providea plurality of ratchet teeth 60 each having its outer end extendingradially inwardly from the peripheral edge of the sprocket wheel.Rotation of the sprocket wheels 32 and 33 is stopped instantaneously byengagement of any of said ratchet teeth 60 by a pawl 61 that projectsoutwardly and perpendicularly from a peripheral edge portion of theplate 57. The base of the pawl 61 is engaged by the free end of thespring 31 which exerts a constantforce urging the plate 57 pivotallyinto the position in which the pawl 61 engages one of the ratchet teeth60 to stop rotation of the sprocket wheels 32 and 33. The plate 5.7 isso shaped that when the pawl 61 is in engagement with any one of theratchet teeth 60, one peripheral edge portion 62 of the plate extendsinto the recess 15.

When a filmstrip 37 is being fed into the magazine; the film passingthrough the restricted zone between the front wall 14 and the sprocketwheels 32 and 33 covers the recess 15, thereby preventing entrance ofthe peripheral edge portion 62 of the plate 57 into the recess 15. Thefilm 37 covering the recess 15 thus prevents pivotal movement of theplate 57 into the position in which the pawl 61 engages one of theratchet teeth 60 to stop the rotation of the sprocket wheels 32 and 33.As the trailing end of the film moves past the restricted zone, itclears the recess 15 and the spring 31 moves the plate 57 pivotallyuntil the peripheral edge portion 62 of the plate 57 enters the recess15 and the pawl 61 moves into engagement with one of the ratchet teeth60 to block the rotation of the sprocket wheels 32 and 33 before theapertures 36 of the trailing end of the filmstrip 37 are separated fromthe sprocket teeth 35. Since the sprocket teeth 35 are still inengagement with the apertures 36 in the trailing end of the filmstrip37,the filmstrip 37 may be fed in the opposite direction, out of themagazine, by merely reversing the rotation of the sprocket wheels 32 and33 without any necessity' of re-engaging the sprocket teeth 35 with thefilm apertures 36.

What is claimed is: 1. An apparatus for retaining the free end of a filmin a cartridge driven by a motor within a projector comprising: storagemeans for the film; means coupled to the projector motor for driving thefilm to and from said storage means; and means sensing the end of thefilm for blocking said driving means to maintain engagement of the filmwith said driving means; said sensing means having a first positiondetermined by the presence of film permitting film movement by saiddriving means and having a second position determined by the absence offilm for stopping film movement by blocking said driving means, saidsensing means being normally urged toward said second position;

said sensing means including a plate having a first position determinedby the presence of film for permitting film movement by said drivingmeans and a second position determined by the absence of film forstopping film movement by blocking said driving means; and

supporting means including a pivot means for supporting said plate formovement between said first and second positions and means for biasingsaid plate toward said second positionabout said pivot I means;

said driving means including a tooth member and said plate including apawl for engaging said tooth member for blocking said driving means.

2. A film cartridge comprising:

a magazine;

a sprocket wheel rotatably mounted adjacent said preventing rotation ofsaidsprocket wheel intone direction; and i a spring biasing said plateagainst said filmstrip and toward engagement with said sprocket wheelwhereby said spring moves said plate into engagement with said sprocketwheel when'the trailing end of the film passes said plate and thetrailing-end" of said filmstrip remains in engagement with said sprocketwheel to permit said rotating means to feed said filmstrip out of saidmagazine.

1. An apparatus for retaining the free end of a film in a cartridgedriven by a motor within a projector comprising: storage means for thefilm; means coupled to the projector motor for driving the film to andfrom said storage means; and means sensing the end of the film forblocking said driving means to maintain engagement of the film with saiddriving means; said sensing means having a first position determined bythe presence of film permitting film movement by said driving means andhaving a second position determined by the absence of film for stoppingfilm movement by blocking said driving means, said sensing means beingnormally urged toward said second position; said sensing means includinga plate having a first position determined by the presence of film forpermitting film movement by said driving means and a second positiondetermined by the absence of film for stopping film movement by blockingsaid driving means; and supporting means including a pivot means forsupporting said plate for movement between said first and secondpositions and means for biasing said plate toward said second positionabout said pivot means; said driving means including a tooth member andsaid plate including a pawl for engaging said tooth member for blockingsaid driving means.
 2. A film cartridge comprising: a magazine; asprocket wheel rotatably mounted adjacent said magazine, said sprocketwheel having a plurality of teeth engageable with apertures in afilmstrip; means for rotating said sprocket wheel in opposite directionswith said teeth engaging said filmstrip apertures to feed said filmstripinto and out of said magazine; a plate operable to engage said sprocketwheel for preventing rotation of said sprocket wheel in one direction;and a spring biasing said plate against said filmstrip and towardengagement with said sprocket wheel whereby said spring moves said plateinto engagement with said sprocket wheel when the trailing end of thefilm passes said plate and the trailing end of said filmstrip remains inengagement with said sprocket wheel to permit said rotating means tofeed said filmstrip out of said magazine.